It has been conventionally proposed to dispose an organic EL panel inside a rear window of a vehicle and use it as a marker lamp, such as a high mount stop lamp or a tail lamp (see, for example, Japanese Patent Laid-open Publication No. 11-198720).
When disposing the organic EL panel inside the rear window, it is required to irradiate the light only to the front side (that is, the rear window side) of the organic EL panel in order to prevent light emitted in the organic EL panel from becoming glare light and dazzling the driver. Also, in order to suppress rearward visibility from deteriorating due to the presence of the organic EL panel, it is required to configure the organic EL panel so that the rear side can be seen through. For these purposes, it has been proposed to configure an organic EL panel to have a light transmission property by forming cathodes in the form of stripes (see, e.g., Japanese Patent Laid-open Publication No. 2015-195173).